Affiliation: Galenic Pharmaceutical Laboratory, UFR Medecine and Pharmacy, Rouen University, 22 Bd Gambetta, 76183 Rouen, France.
The rationale of this study was to investigate the effect of cyclodextrins (β-CD or HPβ-CD) on the dissolution of a poorly water soluble drug: Piroxicam (Px). Interactions of piroxicam (Px) and β-CD or hydroxypropyl-β-CD (HPβ- CD) have been investigated in solution and in the solid state. The phase solubility of inclusion complex for each CD was studied according to Higuchi and Connors method. Equimolecular (Px - β-CD) or (Px - HPβ-CD) solid systems were prepared using different techniques. Solubility studies demonstrated the formation of the (Px - β-CD) and (Px - HPβ-CD) inclusion complexes with 1:1 stoichiometry. In all cases, a significant increase in the dissolution rate with respect to the drug alone was evidenced, which was attributed to the formation of an inclusion compound. The dissolution performance of the complexes appeared to be related to both the preparation method of the solid system and the type of CD used. Among the solid complexes obtained either with β-CD or HPβ-CD, the freeze-dried and the spray-dried systems were the most effective in achieving the enhancement of the Px dissolution rate. The enhancement was better from HPβ-CD than β- CD except for the freeze-drying (P4.2) and the spray-drying methods. The characterization (DSC, TGA, FT-IR and PDRX) showed differences between the complexes and their corresponding physical mixture and individual components.